Passing sql string variable into javascript function

Question

I am trying to pass a string from a query into a javascript function.

An integer will pass into the function but string will not.

echo "<a href='#' onclick='delete_game({$title});' 
class='btn'>Delete</a>";

<script type='text/javascript'>
function delete_game(title){
    var answer = confirm('Really?');
    if(answer){
        window.location = 'delete.php?id=' + title;
    }
}
</script>

I expected the javascript function to be executed, but instead nothing happens.

The string needs to be quoted inside of the function call. delete_game(\"{$title}\") — aynber
– aynber, Commented May 23, 2019 at 13:57
you shouldn't mix PHP + JS - it's bad practice. Inline js/css is also bad practice. — treyBake
– treyBake, Commented May 23, 2019 at 13:58
instead nothing happens I don't think is true. I would expect this to throw a console error. — user3783243
– user3783243, Commented May 23, 2019 at 13:59
@Peter I think that's the preferred - but don't think it's compulsory — treyBake
– treyBake, Commented May 23, 2019 at 13:59
@treyBake You're right. A google search told me it does the same thing. — Peter
– Peter, Commented May 23, 2019 at 14:06

Leonardo Silva · Accepted Answer · 2019-05-23 14:18:53Z

1

Why don't you use ajax for this? As mentioned in comments mix PHP/JS isn't good.

In your HTML, you can do something like

I'm assuming that you are using Blade.

<a href="#" onclick="return deleteGame({$title})">Delete Game</a>

Then in your javascript, you do this using jQuery:

function deleteGame(title){
    var answer = confirm('Really?');
    if(answer){
        $.ajax({
          url : "your-php-file.php",
          type : 'post',
          data : {
               title : title
          }
     })
     .done(function(msg){
          $("#result").html(msg);
     })
     .fail(function(error){
          console.log(error);
     }); 
    }
}

In your PHP you process receiving the data from post $_POST

$title = $_POST['title'];

You can understand better the Ajax function of jQuery here.

answered May 23, 2019 at 14:18

Leonardo Silva

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Comments

Peter · Accepted Answer · 2019-05-23 14:19:36Z

0

A few things:

I would change window.location to window.location.href
Change your echo to:

echo "<a href=\"#\" onclick=\"delete_game('" . $title . "');\" class=\"btn\">Delete</a>";

Check if $title is set

var_dump($title);

If you'd like to make it a bit cleaner and are prepared to use jQuery:

<a href="#" class="btn delete" data-title="<?= $title ?>">Delete</a>
<script type='text/javascript'>
$(document).on('click', '#delete', function () {
   var title = $(this).data('title');
   var answer = confirm('Really?');
    if (answer){
        window.location.href = 'delete.php?id=' + title;
    }
});
</script>

edited May 23, 2019 at 14:19

answered May 23, 2019 at 14:01

Peter

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4 Comments

Ravi Shanker Gowda Over a year ago

Thanks for this it works great. One question though: why do we use a \ before the double quote?

Danyal Sandeelo Over a year ago

@RaviShankerGowda actually delete_game('$title') accepts string value, you can make it as onclick='delete_game('$title'); that would work fine too but when you use " this would break the string so you need to add \" so that It may not break the string

Peter Over a year ago

@RaviShankerGowda It's an escape character. Since you open the echo with "`, you cannot use it in your string without escaping it.

M. Eriksson Over a year ago

@RaviShankerGowda - If you don't want to care about escaping quotes (which makes the code a bit messier), I would recommend simply closing the PHP-tag, write your HTML and then open it again. Something like this: ?> <a href="#"...>...</a> <?php. Then most IDE's can syntax highlight your HTML as well.

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